Upper bridge of a tourbillon



FIG. 1 is a front, left side and bottom perspective view of an upper bridge of a tourbillon showing my new design; and,

FIG. 2 is a front elevation thereof.

The broken line showing of the environment in FIG. 1 is for illustrative purpose only and forms no part of the claimed design. 

The ornamental design for an upper bridge of a tourbillon, as shown and described. 